Checkpoint web parity through Chromium input tasks

tools/web/check-stl-web-roundtrip.py

@@ -0,0 +1,58 @@
+"""Import a browser-produced binary STL in pinned Blender 5.2."""
+
+import hashlib
+import json
+import sys
+from pathlib import Path
+
+import bpy
+
+
+def sha256_file(path):
+    digest = hashlib.sha256()
+    with open(path, "rb") as handle:
+        for chunk in iter(lambda: handle.read(1024 * 1024), b""):
+            digest.update(chunk)
+    return digest.hexdigest()
+
+
+def main(stl_path, report_path):
+    stl_path = Path(stl_path).resolve()
+    report_path = Path(report_path).resolve()
+    bpy.ops.wm.read_factory_settings(use_empty=True)
+    result = bpy.ops.wm.stl_import(
+        filepath=str(stl_path),
+        directory=str(stl_path.parent),
+        forward_axis="NEGATIVE_Z",
+        up_axis="Y",
+        global_scale=1.0,
+        use_scene_unit=False,
+        use_facet_normal=True,
+        use_mesh_validate=True,
+    )
+    objects = [obj for obj in bpy.context.scene.objects if obj.type == "MESH"]
+    if "FINISHED" not in result or not objects:
+        raise RuntimeError("Blender Web STL import did not produce a mesh")
+    mesh = objects[0].data
+    mesh.calc_loop_triangles()
+    report = {
+        "schemaVersion": 1,
+        "operation": "DESKTOP_IMPORT_WEB_STL",
+        "sourceSha256": sha256_file(stl_path),
+        "sourceBytes": stl_path.stat().st_size,
+        "objectCount": len(objects),
+        "vertexCount": len(mesh.vertices),
+        "polygonCount": len(mesh.polygons),
+        "triangleCount": len(mesh.loop_triangles),
+        "polygonNormals": [[float(value) for value in polygon.normal] for polygon in mesh.polygons],
+    }
+    report_path.parent.mkdir(parents=True, exist_ok=True)
+    report_path.write_text(json.dumps(report, indent=2, sort_keys=True) + "\n", encoding="utf-8")
+    print("stl-web-roundtrip-desktop-imported triangles=%s" % report["triangleCount"])
+
+
+if __name__ == "__main__":
+    args = sys.argv[sys.argv.index("--") + 1 :] if "--" in sys.argv else []
+    if len(args) != 2:
+        raise SystemExit("usage: blender --background --python check-stl-web-roundtrip.py -- STL REPORT")
+    main(args[0], args[1])